It is known in the prior art how to communicate to and from a circuit using a data bus. Data busses typically adhere to a bus protocol that defines, among other things, the configuration and function of input/output terminals dedicated to implementing the bus protocol. For example, digital-output microphone systems include a digital data output. A number of digital bus protocols, such as the inter-IC sound (or “I2S”) bus for example, enable microphone systems to transmit digital output data.
It is also known to program or otherwise control portions of a circuit by using control signals, or via a data bus. For example, some bus protocols have various operating modes that can be programmed or re-programmed to adapt to a given application or operating environment. An example of one such protocol is the “inter-integrated circuit” (or “I2C”) bus.
Typically, a circuit includes input/output terminals dedicated to a specific task, such as implementing a data bus or receiving control signals. However, including single-use terminals can be problematic in a small circuit in which there may not be space available to add dedicated terminals. On the other hand, providing multi-tasking terminals typically require considerable overhead in terms of on-board control circuitry and external control programming.